Method for mounting a flexible printing plate onto a printing cylinder

Abstract

The invention relates to a method and apparatus for mounting flexographic printing plate in registration onto a printing cylinder with a mounting bar and a carrier sheet having the plate mounted thereto. The mounting bar and the carrier sheet each have multiple openings which are located to assure consistent alignment between the bar and carrier sheet. The carrier sheet is secured in registration to the mounting bar by aligning the openings of the bar to the carrier sheet and inserting locking pins into the aligned openings. The method for mounting a flexographic printing plate further includes an apparatus for retaining an end of the carrier sheet to prevent its movement while drilling or punching the multiple openings.

We claim: 
     
       1. A method for mounting a flexographic printing plate having a relief image on a printing cylinder having a slot, the method comprising: (a) providing a sheet which is either a carrier sheet having the printing plate attached or the printing plate;   (b) punching at least two openings in the sheet spaced apart in a row parallel to the leading end;   (c) providing a bar having a first arm with a coupling end and a second arm with multiple openings spaced apart in a row parallel to the coupling end;   (d) aligning the at least two openings in the sheet to at least two of the multiple openings of the second arm;   (e) securing the bar to the sheet by placing locking pins in the openings aligned in step d); and   (f) mounting the bar on the printing cylinder so the coupling end of the first arm engages the slot and remains in place on the cylinder during printing.   
     
     
       2. The method of claim wherein the sheet is the carrier sheet having the printing plate attached. 
     
     
       3. The method of claim 2 wherein step a) further comprises: (a1) drilling a second set of at least two openings in the carrier sheet;   (a2) attaching on the carrier sheet the printing plate having registration openings, so that the registration openings in the printing plate align with at least two of the second set of openings in the carrier sheet.   
     
     
       4. The method of claim 2 wherein after printing by the printing plate, the process further comprises: (g) removing the locking pins from the aligned openings in the bar and carrier sheet; and,   (h) reusing the bar on a second carrier sheet.   
     
     
       5. The method of claim 1 wherein the mounting step comprises engaging the coupling end of the first arm to an extended member of the slot. 
     
     
       6. The method of claim 1 wherein the openings at the leading end of the sheet are multiple openings and the shape of the openings are selected from the group consisting of circular shaped and oblong shaped. 
     
     
       7. The method of claim 1 wherein the locking pins have a cylindrical shaft having a diameter and the multiple openings in the bar are circular shaped with a diameter which is the same or substantially the same as the diameter of the shaft. 
     
     
       8. The method of claim 1 wherein the locking pins have a shaft having a locking cap and the securing step comprises: (e1) inserting the shaft of the locking pins into the aligned openings until the locking cap engages a bottom side of the bar. 
     
     
       9. The method of claim 3 wherein the attaching step further comprises: (1) applying an adhesive material to a back of the printing plate;   (2) aligning the registration openings on the printing plate with at least two of the second set of openings in the carrier sheet;   (3) placing mounting pins in the openings which were aligned in step d) to bring the adhesive on the back of the plate in contact with the carrier sheet, and thereby mount the plate one the carrier sheet; and   (4) removing the mounting pins from the openings.   
     
     
       10. The method of claim 2 wherein the sheet further comprises a trailing end opposite the leading end and two side ends, and wherein the method further comprises during the drilling step: c1) retaining at least one of the two side ends or the trailing end.   
     
     
       11. A process for mounting an aligned flexographic printing plate having relief image to a printing cylinder having a slot comprising: (a) providing a mountable flexographic printing element having a relief image comprising: (i) a carrier sheet having a leading end;   (ii) a bar having a first arm with a coupling end and a second arm with multiple openings spaced apart in a row parallel to the coupling end wherein said bar is secured to the leading end of the carrier sheet by locking pins inserted into the carrier sheet and the multiple openings of the second arm, wherein the locking pins secure the bar to the carrier sheet in an aligned manner;   (iii) a least one flexographic printing plate having a relief image attached to the carrier sheet;     (b) mounting the coupling end of the mountable flexographic printing element to the slot of the printing cylinder.   
     
     
       12. A method of manufacturing a mountable flexographic printing element having a relief image, comprising: (a) punching at least two openings in a carrier sheet having a leading end spaced apart in a row parallel to the leading end;   (b) attaching a bar having a first arm with a coupling end and a second arm with multiple openings spaced apart in a row parallel to the coupling end using a plurality of locking pins to the carrier sheet; and   (c) attaching a flexographic printing plate having a relief image to the carrier sheet to form the mountable flexographic printing element.   
     
     
       13. An apparatus for mounting a flexographic printing plate having a relief image on a printing cylinder having a slot, the apparatus comprising: (a) a carrier sheet having a leading end with at least two openings spaced apart in a row parallel to the leading end;   (b) a bar having a first arm with a coupling end for engaging the slot in the cylinder and a second arm with multiple openings spaced apart in a row parallel to the coupling end, wherein at least two of the multiple openings of the second arm are aligned to the openings in the carrier sheet; and   (c) at least two locking pins for securing the carrier sheet to the bar at the at least two aligned openings.   
     
     
       14. The apparatus of claim 13 wherein the at least two aligned openings have a diameter, and the locking pins comprise: a) a shaft having a first end and a second end, and a diameter corresponding to the diameter of the aligned openings;   b) a base perpendicular to the shaft at the first end and having a diameter larger than the diameter of the aligned opening; and   c) a locking cap at or near the second end having a diameter greater than the diameter of the aligned openings.   
     
     
       15. A flexographic printing element having a relief image, comprising: (a) a carrier sheet having a plurality of openings on a leading end;   (b) at least one flexographic printing plate having a relief image attached to the carrier sheet;   (c) a bar having a first arm with a coupling end and a second arm with multiple openings spaced apart in a row parallel to the coupling end; and   (d) a plurality of locking pins wherein the pins secure the bar to the carrier sheet in an aligned fashion through the openings on the leading end of the carrier sheet and on the second arm of the bar.